Subject:
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Re: Grabber arm
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 19 Apr 2000 20:27:40 GMT
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Viewed:
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699 times
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Dave Baum book has a arm that may fit better to your needs. Basically it use
3 motors. One motor controls the torso. The second moves arms up and down.
The third open closes the arm.
You can look at Lego site also and look for user projects. There are some
good solutions.
Tip: Use tires to increase the grip of the arm. You can get pieces (eg:
wheels) using the tip of the "fingers".
Try use this configuration:
"""" """"
===============|==|==
---------------------""""
===============|==|==
======== Beam
-----ou | Axle
""" Gear
The connection between the 2 axles uses a wormgear and a 24t gear for gear
reduction and hold the grip while the motor is stopped. Since both axles are
connected and rotate in diferent directions, they both can be connected to
angle beams to build the grabber.
I hope it helps.
Mauro
"Kerry Raymond" <kerry@dstc.edu.au> wrote in message
news:kerry.956117077@dstc.edu.au...
> I downloaded the instructions for building a grabber arm from the
> Mindstorms WWW site (I gather this is the grabber arm depicted on the
> 1.5 box).
>
> However, I found that the arm wasn't very good at actually picking things
> up. Although I didn't have the exact pieces in a couple of places (I don't
> have v1.5), I don't think any of my substitutions would have affected the
> mechanics of it.
>
> In particular, the way the "hands" closed altered the height of the
> grabbing action as the hands closed. This made me think that I needed to
> synchronise the hand opening/closing movement with a bit of arm up/down
> movement but to date, I haven't developed a successful combined movement.
>
> However, I wondered if I am wasting my time as the arm may have been
> designed to look good on the box top rather than be a useful grabbing arm.
> It certainly is more complicated that other ones out there.
>
> Any comments on this arm from anyone else who has built it?
>
> Kerry
>
>
============================================================================
=
> Dr Kerry Raymond, Distinguished Research Fellow E-mail: • kerry@dstc.edu.au
> CRC for Enterprise Distributed Systems Technology Phone: +61 7 3365 • 4310
> University of Queensland 4072 Australia Fax: +61 7 3365 • 4311
> =========================================== WWW:
http://www.dstc.edu.au/kerry
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Message is in Reply To:
 | | Grabber arm
|
| I downloaded the instructions for building a grabber arm from the Mindstorms WWW site (I gather this is the grabber arm depicted on the 1.5 box). However, I found that the arm wasn't very good at actually picking things up. Although I didn't have (...) (25 years ago, 19-Apr-00, to lugnet.robotics)
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